The tool holder assembly is connected to a conventional drive spindle. The tool holder is received in a rotatable spindle. The tool holder has an elongated body having an axial bore in the lower end. The cutting tool includes a stepped shank that is telescopically received in the body. A retention sleeve cooperates with a cammed pin to releasably interlock the cutting tool to the tool holder body by drawing the cutting tool into a contoured axial opening in the body.
In my previous U.S. patent application Ser. No. 11/619,666 filed Jan. 4, 2007, which is incorporated herein by reference, I described a cutting tool shank and the tool holder having complementary polygonal drive sections that ensure that there are multiple flat surfaces that create an interference fit upon rotation of the cutting tool and resist deflection when the cutting tool is cutting. The interference fit provided a desired resistance to deflection or rigidity between the removable cutting tool and the machine mounted tool holder. This polygonal drive section, however, utilizes an axially mounted threaded member or “drawbar” that pulls the cutting tool into the tool holder. While the drawbar configuration is effective to rigidly mate the cutting tool and tool holder, the tool holder must be removed from the spindle to change cutting tools.
The present invention eliminates the drawbar while providing a rigid interference fit between the cutting tool and tool holder. Complementary oval or elliptical shaped drive portions are provided allowing the cutting tool to partially rotate within the tool holder until opposite facing portions of the outer wall of the oval section of the cutting tool's shank abut a complementary-shaped, albeit slightly larger, inner wall of an opening in the tool holder.
The present invention further includes a cylindrical retention sleeve which is received within the tool holder opening ahead of the cutting tool shank. The sleeve includes an eccentrically shaped opening that receives a lobed head on the end of the shank prior to rotating the shank within the tool holder, once the shank is rotated within the tool holder and the drive portions abut, the lobed head is locked axially within the eccentric sleeve opening. A cammed pin passing laterally through the sleeve and tool holder draws the sleeve and the interlocked shank into the tool holder.
The broad purpose of the present invention is to provide a tool holder chucking structure providing a positive drive member and limiting movement of the cutting tool relative to the tool holder while allowing the cutting tool to be quickly connected and disconnected from the tool holder.
One advantage of the present invention is that is provides a cutting tool to tool holder interface having two distinct sections: an oval interface and a tapered interface.
Another advantage of the present invention is that it includes a third cylindrical interface between the cutting tool and tool holder that resists movement of the cutting tool along the angled profile of the tapered interface.
Still another advantage of the present invention is that it provides a quick disconnect feature allowing the cutting tool to be rapidly and easily removed from and attached to the tool holder to minimize machine downtime.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.